Here's a new drinking game to try on your 21st birthday: Jell-O shot Twister, invented by Jimmy Fallon on Monday night's Tonight Show. The rules are simple — every time you land on a new spot, you take a colorful shot. Whoever falls down first is the Loser with a capital L.

Kristen Stewart and Fallon were happy to give the game its inaugural spin. The blazers came off, and at first everything went perfectly. Then their (lack of) flexibility got the best of them, and they needed someone to literally feed them Jell-O shots as the game went on.

"These are gargantuan shots," Stewart said. She downed six total.

"You don't have to premiere anything tonight, do you?" Fallon laughed. Watch their ridiculous antics in the video below.